Method of forming tanks of spherical configuration



April 4, 1950 R. J. BRANSON 2,503,191

METHOD OF FORMING TANKS OF SPHERICAL CONFIGURATION Filed June 30, 1947 Pic. 4 Ficr. Z

INVENTOR. [2.0. EmANsou Patented Apr. 4, 1950 METHOD OF FORMING TANKS OF SPHERICAL CONFIGURATION Raymond J. Branson, Tulsa, Okla, assignor to McNamar Boiler & Tank Company, Inc., Tulsa., Okla., a. corporation of Oklahoma Application June 30, 1947, Serial No. 758,148

4 Claims.

This invention relates particularly to the meth- 0d of forming spherical containers, and more particularly but not limited thereto, to the forming of spherical tanks adapted to be used in the storageand transportation of fluids under pressure, such as liquified petroleum gases and volatile liquids. The present invention is similar and relates in subject matter to applicants co-pending application, Serial Number 739,789, filed April 7, 1947.

This invention differs from the conventional methods of forming spheroid or spherical tanks that normally utilize dies and die machinery and is concerned with the method of forming spherical bodies by the hydraulic application of a fluid, such as oil or water, to a closed body of particular configuration, and in such a manner that the body is expanded or bulged by the hydraulic pressure to form a substantially symmetrical spheroid. The hydraulic method employing oil or water to create expansion has many'advan tages, and the particular advantage that all or the greater part of the metal may be uniformly stretched or elongated to maintain a uniform thickness throughout the body in the reshaping thereof to a substantially spherical configuration.

The present invention is distinguished from the aforementioned application in that it is more specifically utilized for forming spheroids wherein a decreased or lesser amount of elongation of the material is necessary, thereby requiring less thickness in the material, and more particularly is distinguished by the use of materials having a higher tensile strength.

It is an important object of this invention to provide a novel method of forming a high preswithout the use of dies, molds or the like.

And still another object of this invention is to provide a method of forming spherical bodies by hydraulic expansion.

And still another object of this invention is to form a spherical body by the application of hydraulic pressure in such a manner that the finished spherical body is assured of a safety factor to prevent bursting that is within the confines of the A. S. M. E. Code.

And still another object of this invention is to form a spherical container from a pre-formed body of substantially cylindrical shape in crosssection by employing hydraulic pressure to expand or reshape the pre-formed body into a substantially symmetrical spheroid. I

And another object of this invention is to form 2,, a spherical container from a pre-formed body of longitudinal cylindrical shape having inclined end portions by the employment of hydraulic pressure to expand the pre-iormed body into a spheroid without any substantial elongation of Y the metal during the expansion.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

In the drawings:

.Figure 1 is a sectional elevational view of the body prior to the reshaping thereof. Figure 2 is an end elevational view of Figure 1 Figure-3 is an elevational view showing the body expanded into a spherical configuration.

Figure 4 is a detailed view showing a modification of the body in Figure 1.

Referring to the drawings in detail, and more particularly Figures 1, 2, and 3, the novel method utilized herein comprises forming a substantially cylindrical shell 2 by rolling a metal sheet of desired thickness on a forming roll (not shown) intoa cylindrical configuration welded at 3. The

opposite ends of the formed cylinder are closed, thus providing a cylindrical body as clearly shown in Figure 1. The opposite longitudinal ends of the cylindrical body either prior to the cylindrical formation or afterwards as desired are rolled by any conventional means (not shown) to provide a flanged portion 4 disposed at an incline to the cylindrical body. The flanged portions 4 are preferably disposed at a 45 degree angle but are not limited thereto. The cylindrical body 2- with its inclined flange ends 4 is adapted to be ,closed by end plate members 6 having their oil.- cumferential edge provided with a flanged portion 8 disposed at an angle or incline thereto. It will be apparent from Figure 1 that the angularity or inclination of the flanges 8 is substantially equal to that of the flanges 4 for the cylindrical shell 2. g

The angular disposition of the flanges 4 and 6 may be varied to within practical limits, however in forming the flanges it is essential that the length of the flange portions 4 and 8 be substantially the same in order to expand the closed body in the manner hereinafter referred to. It will be understood that the length of the shell or cylinder 2 and the diameter of the end portion '6 may be varied within practical limitations, however the length of their respective flange portions 4 and 8 should be substantially equal. The predetermined dimensional ratio of the end bers 6 are secured to the cylinder 2 by welding at the jointure of the flanged members 4 andt respectively to provide a circumferential weld HT. The closed cylindrical body 2 is provided with a coupling member I2 welded thereto" in order to provide an inlet aperture providing communication with the interior of the closed shell 2, and pumping equipment (not shown) for supplying hydraulic medium, such as oil or water, similar to that disclosed in applicants aforementioned co-pending application.

The closed vessel 2 is filled with the hydraulic medium to build up the pressure, and continued discharge of the hydraulic medium with an increase in pressure into the closed body 2 will cause an expansion thereof. The increased hydraulic pressure will expand or bulge the welded flanges and 8- fromthe inclined contour as shownin Figure 1, to reshape'them into a curvature-substanti'ally onthesegment of acircle.

It will be apparentthat the shell section 2 and the end sections 5 are simultaneously expanded to be reshaped by the hydraulic pressure into a substantially symmetrical spheroid bodygenerally indicated at It, as is clearly shown in Figure 3. The present method utilizes a hydraulic medium to form a spherical vessel from a pre-formed cylindrical body having inclined flanged end portions, without-the use of any dies to assist in the shaping of the material during the formation period.

The material utilized in forming the closed cylindrical body 2 may be the sameas any other material that is conventionally used for'pressure vessels of this type, however, the particular com figuration of the body, as shown in Figure i is preferable in order to beutilized with materials having a high tensile strength in order to cause the expansion into a spherical body without any appreciable elongation or stretch of such material. It will be apparent that the decreased elongation with materialsof high tensile strengths will permit the storage of high pressure fluids with a material of less thickness, than that of low tens le strength materials. This isp'articularly advantageous'in reducing the overall weight and particularly the shipping weight of the completed spherical container, at the same timeproviding a spherical'container having a theoretical bursting pressure within the confines of the safety factor of the A. S. M. E. Code, as particularly set out in applicants'co-pending application;

It is to be understood that the present invention is not' limited to materials of" high tensile alloy steels, but the cylindrical body 2 with the flanged ends 4 and t'may utilize lo'wtensile alloy steels as well. The formation of the-inclined flanges permits the use of high' tensile alloy steels and particularly the expansio thereof by hydraulic pressure without any appreciable elongation or stretch in the material which will eliminate considerable molecular distortion that may be created due to the elongation. V

In practice, it may bedesirable to-p'rovide a circular backing ring" on theinner'periphery of the flanged ends 4 and 8 and particularly adjacent the weld H], as clearly shown in Figure 4. The flange ring I4 is provided to support the weld It during the expanding or reshaping of the closed body. Furthermore, external molds, such as substantially circular rings (not shown) may be disposed on the exterior of the closed vessel to assist in the shaping or forming of the spheroid in conjunction with the hydraulic expansion. It will be apparent that the use of the circular ring M or the external rings is not necessary to a practical application of the invention, and the spheroid may be formed by the application of hydraulic pressure as stated above.

From the foregoing it will be apparent that the present invention provides for the forming of a container of spherical configuration from a body of substantially cylindrical shape wherein the ends are bent or formed on an incline in order to co-operate with end plate members having bent or formed flanges adapted to be welded to the inclined flanges of the cylindrical body. Furthermore, the inclined flanges of both the cylindrical body and the end plates are formed with pre-dete'rmined dimensions so that the cooperating flanges will' be of substantially equal length, and of substantially equal inclination. The particular configuration of the pre-formed body will allow for the hydraulic expansion of high tension alloy steels which are normally dif-' ficult to reshape or bulge and particularly allow for the expansion without any material elongation or molecular distortion of the metal in order that a spherical container for fluids may be formed which is much lighter in weight and yet fall within the confines of the necessary bursting pressure under the A. S; M. E. Code. The inclination of the flanged portions for the closed body will facilit'atere-shaping of the body simultaneous with the longitudinal cylindrical section in order to bulge or expand the body intoa substantially spherical shape.

Changes may be made in the specification and drawings without departing from the spirit of the invention within the scope of the following claims, as set forth.

What I claim is:

l. The'methodof forming a spherical container which consists of constructing a cylindrical body with inclined flanged portions at the opposite ends thereoflforming substantially flat end plates having inclined flanges, welding'the meeting ends of the opposing flanges to close the cylindrical body, providing a substantially'e'dual ratio between the inclination and length of the flanges of the cylindricalbody and the end plates, expanding the closed body with internal hydraulic pressure'to reshape the body into a substantially spherical configuration.

2: The methodof forming a spherical-container for fluids which consistsof constructing a cylindrical body having angular d'is'p'osedflang members at the opposite ends-thereof, forming substantially flat closure plates having an. angular disposed circumferential flange, said flanges of substantially equallengthand inclination, welding the contacting ends" of the opposing flanges to close the cylindrical body, expanding the closed body with internal hydraulic pressure for reshaping the body into a spheroid.

3; The method of forming a spherical container which consists of forming a cylindrical body having inclined flange portionsat the opposite circumferential edges thereof, closing the open ends of the cylindrical body with substantially flat end plate members welded thereto, forming said plate member with inclined circumferential flanges co-operating with the inclined flanges of the body, said flanges of substantially equal inclination, welding the contacting edges of the flanges, expanding the closed body with internal hydraulic pressure for reshaping the body into a substantially spherical configuration.

4. The method of forming a spherical container which consists of constructing a cylindrical body with a circumferential flanged portion at the opposite ends thereof and disposed at a substantially 45 degree angle to the longitudinal axis of the body, forming substantially flat end plates for the body having a circumferential flange disposed at substantially 45 degrees to the axis thereof, forming the flanges on the end plates and the body of substantially the same dimensional length, welding the meeting ends of the opposing flanges for closing the cylindri- 6 cal body, expanding the closed body with internal hydraulic pressure for reshaping the body into a substantially spherical configuration.

' RAYMOND J. BRANSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

